I've just started learning Ruby on rails and I am wondering how to do something that I know how to easily do in PHP.
I want to create some basic web services that can be called with POST parameters and send a JSON as a response. I don't know at all how to start with that using Ruby on rails.
I am sure there are some best practice to do that kind of things, so if you guys could advise me anything, it would be great!
Regards,
To get the POST parameters, you just look into the params hash in your controller, which will have any and all parameters for the request, whether they're coming as POST params, GET params, or as part of the route (e.g. /users/:id/new => params[:id] in the controller)
To return json from the request, you'd just make a render call like this:
render :json => #model
Beyond that, your question is a bit broad for the scope of an answer on SO. I recommend reading Agile Web Development with Rails as a starting point to learn Rails development.
Sounds like a good fit for Sinatra. Check out http://www.sinatrarb.com/
The great thing about rails is that it is based on the principal of REST.
Whenever you create a RESTful resource, you are in fact creating a web service at the same time.
For example. Say you create a resource using a scaffold generator.
rails g scaffold Feed title:string content:string
This will not only create all the view logic in HTML, but also in xml.
Further to your first comment:
If you look in the controller, within the respond_to block you can specify the return type. So you want to hit the xml version of new and return the json version of create.
To render your treated parameters to json, put them in a hash:
js = {:my => {:json => 'hash'}}
render :json => js
Related
I'm making a versioned JSON API in rails, where the controllers also respond to HTML, meaning it can be accessed as a browser or through an app I'm developing. The controllers have the form Model::V1::UsersController (Model instead of API since they don't just respond to JSON), and I currently have the following in my routes.rb:
namespace :model, path: 'm', as: '' do
# For objects in the model, accessible by JSON (through the app) or HTML (through the browser, using forms to send data to the server).
scope module: 'v1', constraints: OrConstraint.new([APIConstraint.new(1), APIConstraint.new(:default)]) do
resources :users do
collection do
post :sign_in
end
end
end
end
I plan to add more models to my API, but how can I use scaffolding to do this? For example, to create a controller Model::V1::CommentsController, but using the Comment model, instead of Model::V1::Comments.
I've been trying to figure this out for hours, and googling for people with similar problems shows that a few people say not to use scaffolding at all in this case: I don't want to do this, as it would mean writing all the views myself, which would be very time-consuming. Apart from that, I can't find much. nifty-generators was suggested somewhere, but it doesn't seem to be maintained anymore: no activity since 2012. I'm new to rails, and it might be that I've missed something quite obvious, but I find it surprising that not many others have had the same issue.
I've considered making my own generator, but looking at the source of https://github.com/rails/rails/blob/master/railties/lib/rails/generators/rails/scaffold/scaffold_generator.rb, it seems very complicated.
EDIT: I've just discovered that I can pass the --model-name parameter to the rails scaffold generator to achieve what I want, but for some reason it still tries to create a model with the same name as the controller. How can I change this?
I've settled with this solution, by not generating a model at all using the scaffold generator:
To create Model::V1::CommentsController as the controller and Comments as the model:
rails g model comment
rails g scaffold model/v1/comments --model-name=comment --no-orm
I'm writing a rails application with an AngularJS front-end, this is part of a tutorial series I'm writing on connecting rails and angularjs. This means my rails application communicates with the browser exclusively in JSON.
In the angularjs $http documentation it describes a potential json security vulnerability where the json request can be embedded into a script tag, plus some tricky use of jsonp, to allow something akin to a cross-site scripting attack. I've found a few other pages, one in particular I thought described this well, and dates from 2008, so this isn't a new issue.
Apparently this isn't a vulnerability in standard rails json rendering, as rails by default provides back an object containing an array. But when working with angularjs we appear to set root: false (although I have to confess I can't find where I did that, but it's definitely not giving the root node).
Anyway, the bottom line is that the angular documentation recommends prefixing any json response with )]}', so:
['one','two']
Becomes
)]}',
['one','two']
Angular then automatically strips that off again.
I'm looking for a way to do this elegantly. I've seen a lot of questions and answers on stackoverflow about this, but most of those either relate to much earlier versions of rails before JSON handling was more thoroughly embedded, or seem to require me to create a lot of boilerplate code. I'm looking for a method that I can apply to the application controller, or as a helper method, that will work everywhere.
The controller that I'm currently using looks as follows:
class ClubsController < ApplicationController
respond_to :json
# GET /clubs.json
def index
#clubs = Club.all
render json: #clubs
end
end
This doesn't call any templates - the render action skips the templating engine. I can get this working by changing the render line instead to:
respond_with json: #clubs
And creating a template file views/clubs/index.json.erb that contains
)]}',
<%= raw(#clubs.to_json) %>
But I'd then have to create a template for every action on every controller, which feels like boilerplate. I'd like instead to be able to change views/layouts/application.json.erb to have something like:
)]}',
<%= yield %>
But that doesn't work because we only get templating if we call respond_with. And if we call respond_with, we have no way to put the #clubs into the response - so we end up with:
)]}',
As the entirety of the response.
An alternative would perhaps be to override the as_json method to prepend what I want, but that seems a bit like a sledgehammer. Ideally there would be a place I could introduce a helper method, something like:
render prepend_vulnerability_protection(json: #clubs)
So, after all that, two questions:
Is this even a real problem, or does Rails already have some other protection that means I don't need to worry about this at all
Is there a way to do this centrally, or do I need to bite the bullet and create all the boilerplate templates? I can modify the scaffold generators to do it, so it's not the end of the world, but it does seem like a lot of boilerplate code
So, no responses as yet. I'm going to write down what I find from my research, and my current answer.
Firstly, I think this is a genuine vulnerability in rails. Unfortunately the rails and JSON/JSONP area has had some other recent vulnerabilities relating to the JSON parser at the Rails end. That has really drowned out any google search relating to this specific XSS issue.
There are a couple of approaches to resolving this:
Have your application only respond to put/post/delete requests. That's not really an option when integrating to Angular - well, it is, but it means overriding a bunch of standard behaviour
Insert something at the front of your returned JSON - this can be the root node (default rails behaviour in rails 3, no longer in 3.1), a closure like )]};, or a loop like while (1);. Angular expects and can deal with )]}',
I've looked at using a json template in my rails app. You can do this with one of many gems, the one I like the look of is JBuilder (railscast 320), but RABL is perhaps more powerful (railscast 322).
This does mean a template for each of the actions on each of the controllers. However, I've also just completed working out how to have rails scaffold those for me automatically, so it's not as scary as it was when I first asked the question, and I can see some other reasons that I might want more control over the json that is returned from my application.
Having said that, I couldn't immediately see a way to get JBuilder to prepend an arbitrary string - it seems to only want to prepare valid JSON (and this I think is not valid JSON). RABL looks like it can do it, but it is a bit more complex. It can definitely be done through just using ERB, but I feel kinda wrong in doing that.
The other alternative I've identified is a helper method in application_controller.rb, which I then call in each of my controller methods. This is reasonably elegant, and I can quite easily change my template to do it. So I'm going with this for now:
class ApplicationController < ActionController::Base
def render_with_protection(json_content, parameters = {})
render parameters.merge(content_type: 'application/json', text: ")]}',\n" + json_content)
end
end
class ClubsController < ApplicationController
respond_to :json
# GET /clubs.json
def index
#clubs = Club.all
render_with_protection #clubs.to_json
end
# GET /clubs/1.json
def show
#club = Club.find(params[:id])
render_with_protection #club.to_json
end
# POST /clubs.json
def create
#club = Club.new(params[:club])
if #club.save
render_with_protection #club.to_json, {status: :created, location: #club}
else
render_with_protection #club.errors.to_json, {status: :unprocessable_entity}
end
end
end
Note that you should be also including CSRF protection in your application controller - so see this as additive to the security precautions you were already taking, not a replacement.
The different Rails 3/Ajax solutions I have come across show examples that retrieve data from a database.
I would like to make an Ajax call and have the server return data that does not come from a database. The data actually comes from REST aware pages on the web.
Any suggestions or examples?
See this example:
# Use the class methods to get down to business quickly
response = HTTParty.get('http://twitter.com/statuses/public_timeline.json')
puts response.body, response.code, response.message, response.headers.inspect
With HTTParty gem.
You will return results as usual with Rails, for example, you could call in your controller:
render json: response.body
If you want it AJAX you can call this controller I mention with:
$.get('my_rails_route');
Check your requirements, you could simply do:
$.get('http://twitter.com/statuses/public_timeline.json');
Without passing by Rails server.
I would like to do that's the best way of actually accomplishing the
following on Rails.
I have a "Booking Form" with 5 fields (Property, Amount of Children,
Amount of Adults and 2 Dates - Departure and Arrival) based on these
fields, I need to construct an URL and redirect the user to this url.
Now, I have 2 questions.
1) How i catch the POST parameters in the controller, because I'm
mapping the form to an action like this:
<% form_tag(:action => "booking") do %>
and routing it to a controller action like this: (Pages Controller,
Booking Action)
match 'pages/booking' => 'pages#booking'
2) Is this the Rails way of actually accomplishing such thing?
I did it this way in PHP in the past, but now I have the need of
actually doing it in Rails, could you Rails Gurus inspire me ?
To access parameters in the controller, even ones submitted in a POST body, use the params hash. Eg: params[:form_field]
To redirect to another URL using a controller, use redirect_to. You can certainly use the values in params to construct a URL and pass it to redirect_to.
If you're using resourceful routes, which is the best way to go about such things, you would route things through the traditional approach:
resources :bookings
Then you'd post the form to bookings_path and it would all work out, as that's BookingsController#create. It's always better to have a strong correlation between model and controller where possible.
The resources definition in routes.rb helps you by creating all the default RESTful actions which you can build off of. If you really need a custom route, you can always rename it using the :as option, or route it independently.
If you go about creating your own arbitrary routes, such as /pages/booking you're going to create quite a mess that someone else will have to maintain. Quite often that someone else is you in the future.
I am working on a rails application (I have some experience with rails). But, this time I am using RESTful to build it. I am wondering how do I validate my models in a RESTful fashion? What I mean by that is when a user enters data into a form, but the model validations prevent the model from being created what is a RESTful way to redirect the user back to the new action with the data they entered still present in the form?
REST only affects your controllers and routes!
Model validations in a RESTful Rails app are the same as the validations in any other Rails app.
Josh - you mention wanting to know how to redirect the user back to create if it errored out. If you are use to earlier versions of Rails just make sure you are using the form_for helper rather then the start_form_tag from early. Your controller code will look pretty similar to how you might be used to... for example (a Customer model):
def create
#customer = Customer.new(params[:customer])
if #customer.save
flash[:notice] = 'Customer was successfully created.'
redirect_to(#customer)
else
render :action => "new"
end
end
You'll notice now the redirect_to(#customer) that forwards to the record that was created in the transaction. But on failure it's the same old render :action.
Whether developing in a RESTful or regular fashion, the backend implementation remains generally the same. Just as in a non-RESTful app, you would simply re-render the create page with the form with the instance the user is trying to create. Really with REST, all you are doing is creating a uniform set of URLs which respond to different HTTP requests, everything else remains the same.
use the scaffold generator to view the example codes on restful controllers